Abstract: :
Purpose: To improve the visual performances of the Age-relatedMacular Degeneration (AMD) individuals by presenting them enhancedimages that make use of the observer's filling-in mechanism.Methods: Age-related Macular Degeneration (AMD) damages theretina and causes retinal scotomas, regions at which visualstimulation is not available. In spite of these blind spots,the images perceived by the patients are usually continuous,and at the same time distorted in certain ways. The abnormalperception cannot be corrected by current clinical or opticalmeans, and prevents many AMD individuals from performing ordinarytasks, such as watching TV and reading. The results of our fouryears research shows that the main mechanism responsible forthe AMD perceptual effects is a cortical «filling-in»process that operates on lines, edges, and texture patterns.The filling-in process causes partial completion of the imagesacross the scotomas and induces the perception of continuousimage. We herein present a new technique of image enhancementthat makes use of the filling-in mechanism of the AMD observer,enabling him/her to perceive the images better. For example,making the lines and edges in the image sparser and emphasizingonly the relevant ones make the perception easier. On the otherhand, making two dimensional texture pattern denser often enablesthe perception of complete pattern. We tested the efficiencyof the technique by measuring the minimum image size that enablesAMD subjects to recognize familiar faces, objects, and to read.In addition, we measured the visual performances and impressionwhen watching enhanced video images. We compared the resultsof 37 subjects with their visual perception and performanceswhen watching the original and natural Images.Results: We foundthat AMD subjects can recognize familiar objects and read inenhanced images that are in average smaller than 50% of theminimum size required to recognize and read in the originalimages. More than 70% of the subjects that had difficultiesin watching the original video images, preferred to watch theenhanced ones. As the visual acuity of the AMD subjects decreased,the percentage of preference for the enhanced images increased.Conclusion: Enhancing the relevant features of the image, ina way that enables them to be filled-in better, significantlyimproves the perception of the AMD individuals. The implementationof the technique can lead to a new medical apparatus that willenable the patients to watch TV and read more easily.